The present invention pertains to adsorbents having low beverage soluble iron content in beverages, such as beer.
Silica gels have been used to remove certain undesirable components from a certain beverages, typically by adsorption. For example, silica gels have been used in brewing processes to stabilize beer by adsorbing lower molecular weight proteins (e.g., less than 40,000 daltons) that are generally responsible for haze formation. Commercial silica gels are manufactured from silicate solutions and mineral acids and contain small quantities of metals, such as iron, that are partially soluble in beverages and contaminate them. The portion of the iron content of the silica gel which is soluble in a beverage is known as xe2x80x9cbeverage soluble ironxe2x80x9d (often abbreviated as xe2x80x9cBSIxe2x80x9d). Although an adsorbent""s BSI can be readily identified, the BSI varies with different beverages, pH""s, and temperatures, among other factors. Such dissolved metals may destabilize colloidal constituents of beverages, inducing lower quality. For example, high dissolved iron levels adversely affect beer taste and shelf life.
Some efforts have been made to stabilize beer and more specifically to treat beer to prevent chill haze and metal contamination. For example, U.S. Pat. No. 4,134,857 to Bradley discloses reducing the BSI by washing a filter aid such as diatomite with an aqueous solution of tannic or gallic acid or mixtures thereof, with the aid of citric acid for color control.
The presence of high iron levels in beverages can be deleterious to the taste and long-term stability (xe2x80x9cshelf lifexe2x80x9d) of the beverage. Accordingly, it would be advantageous to have a cost-effective adsorbent having a low BSI.
In view of its purposes, the present invention provides an adsorbent having a low beverage soluble iron (BSI) content for use in the removal of certain components from a beverage to reduce chill haze. The adsorbent is made by introducing a polyphosphate sequestering agent during the production of the adsorbent. In particular, the process involves contacting a polyphosphate sequestering agent, such as sodium tripolyphosphate, with a reactant of a silica gel or a wash solution containing a precursor of the silica gel, or both. The reactant may be a sodium or potassium silicate solution used in conjunction with a mineral acid to make a silica hydrogel. The precursor may be a silica hydrogel formed by mixing a sodium or potassium silicate solution with a mineral acid. From the precursor, the adsorbent is formed. Thus, the composition of the present invention is an adsorbent comprising a silica component and a polyphosphate sequestering agent component.
The present invention also provides for a process of using the adsorbent to reduce certain contaminants from beverages. The process and composition of the present invention allow for the removal of contaminants which tend to form chill haze in beer, for example. The process involves contacting a beverage with an adsorbent of the present invention to adsorb at least a portion of the components then separating the adsorbent from the beverage, such as by filtering.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but not restrictive, of the invention.